Published On: Thu, Jul 16th, 2009

Logic Tutorial: EXS24 Parameters

If you know your way around the EXS24’s Parameters window you can transform Logic’s sampler instruments in extreme ways. Mark Cousins pushes the envelope in this Logic Tutorial




Although we’ve explored many of the deeper aspects of Logic’s EXS24 (sample mapping and data management were both covered in the recent Logic Focus issue), we’ve yet to fully explore its front end – the Parameters window.

The EXS24 is undoubtedly one of the most useful production tools in Logic, so it’s interesting to note some of the features contained within the plug-in’s interface. Indeed, whether you’re importing REX files into the EXS24 or using the sampler’s filters and envelopes to manipulate raw synth waveshapes, there’s a lot that can be achieved with the various tools on offer.

Two-tier Editing

Before we dive too deeply into the EXS24’s parameters, it’s important to understand the two-tiered workflow approach that Logic’s sampler utilises. Sample mapping is handled by the Instrument Editor, while the settings for the synthesis engine are found in the Parameters window. Intriguingly, these two aspects of the EXS24 are somewhat independent of one another – it’s even possible to move one instrument’s parameter settings to another.

And while this may sound rather complicated at first, it ultimately provides you with more flexibility (assuming, of course, that you remember to save the parameter settings with the instrument once you’ve finished editing).


Filter Fun

Some of the EXS24’s most exciting controls relate to its filter section, enabling you – among other things – to gouge out harmonic components of the original samples. This is particularly effective if you’re using samples with rich harmonics – raw synth waveshapes (like the sawtooth buzz patch in the coverdisc Workshop folder), distorted guitar or drum loops.
By default the filter is deactivated, so you’ll need to click on the button currently labelled ‘off’ to activate it. The principal controls are Cutoff and Resonance, with the various filter modes (high-pass, low-pass and band-pass) and strengths (varying between 6dB and 24dB) selectable from the tabs at the bottom of the filter section.

In addition to Cutoff and Resonance, the EXS24’s filter section also contains other useful controls. Drive adds a small amount of distortion ahead of the filter, creating an output that’s slightly fuller and increasingly dirty. This is a great way of warming up synth-like sounds and yields an output that is similar to a Minimoog filter being overdriven. The Fat control reduces the ‘thinning’ effect of high Resonance settings, which is useful if you want to add resonance to a bass sample, for example, but don’t want to lose its power in the low end of the mix.

One point to note about the EXS24’s filter is that the samples are generally processed en masse, unlike some other software samplers (including NI’s Kontakt) which enable different keygroups to have independent filter settings. However, if you delve into the Instrument Editor (press the Edit button on the Parameter window and select the Group view on the left-hand side) it is possible to change the relative Filter Offset value on a group-by-group basis. Try this on the 808 Kit, changing the relative amount of filtering applied to the snare group.

If you require a completely different filter type (band-pass rather than low-pass, perhaps) you’ll need to resort to another instance of the EXS24.

Enter the Matrix

As with many of Logic’s synths, the EXS24’s modulation matrix forms an important part of what can be creatively achieved with the instrument. The system works in much the same way as the patch cords on a modular synth, which route a modulation source (velocity, for example) to a modulation destination (an EXS24 parameter). You can view the sources (src) and destinations (dest) via the dropdown menus in the modulation matrix, using the adjacent slider to set the relative strength of modulation. Try setting Velocity so that it has full control (+100%) over the filter cutoff.

The creative possibilities of the modulation matrix really come to the fore when you start thinking about dynamic ways of manipulating and controlling your sample data. Look at the ‘Pulsing Pad’, for example. In this instance, a simple 16th pattern using MIDI CC1 (created in the Hyper Editor) is being used to modulate the cutoff of the filter, creating a repetitive filter movement over the basic chords.

Another modulation effect is to modulate sample start. This is put to interesting effect on the ‘Synth Sweep’ instrument. The core sample is an evolving synth sweep sampled from an analogue synthesizer. However, by using velocity mapped to sample start we can trigger the note from different points in the original sample, effectively creating a form of sample-and-hold effect.


Pushing the Envelope

The EXS24’s envelopes have a range of useful applications, from smoothing out the attack of a pad sound to creating long filter-sweep effects, but some of the most beneficial applications relate to processing REX loops. You can convert and import REX files (like the one included in the coverdisc Workshop folder) using the menu options Instrument> ReCycle Convert>Extract MIDI Region and Make New Instrument from the EXS24’s Instrument Editor. A MIDI region will be created for the loop, plus a newly ‘sliced’ instrument in the EXS24.

By default, Envelope 2 is always hard-assigned to the amplifier. If you’re importing a loop and speeding it up, for example, you might want to change the Decay and Release settings (with Sustain at zero) to make the envelope for each slice slightly shorter. Going further still, you can even use choppy Decay and Release settings to produce an abstract ‘clicking’ effect (this is particularly interesting if you also raise the pitch of the slices using the Tune parameter).

Envelope 1, of course, is freely assignable, so you’ll need to connect it to a destination parameter (filter cutoff, for example) before it will work. Going back to our REX loop, try using Envelope 2 to create a quick filter sweep across the front of the sound – use a quick Attack, no Sustain and adjust the Decay and Release settings to define the length of the sweep.

You could even use the Via option located in the modulation matrix to define the relative strength of modulation (the amount of sweep, in other words) using another source. This could be velocity, for example, or the modulation wheel.


Low-Frequency Action

Other useful modulation sources are the EXS24’s three assignable LFOs, each of which has its own unique characteristics. LFO 1 is polyphonic, making it the best choice for effects such as vibrato on big string pads. LFO 2, on the other hand, is monophonic, making the oscillation the same irrespective of how many keys you hold down or when they’ve been triggered.
Both LFO 1 and LFO 2 can be set to a variety of waveshapes, from a conventional sine wave used for vibrato through to complicated sample-and-hold patterns that work well when mapped to the filter.

Finally, LFO 3 is the simplest of the three, being monophonic and fixed to a sine waveshape.
All of the LFOs can, of course, be tempo-sync’ed by positioning the Rate parameter somewhere before its 12 o’clock setting. Try experimenting with the tempo-sync’ed LFOs using some of the more unusual waveshapes mapped to the filter.


Set and Save

As we mentioned at the start of this Workshop, it’s important to remember that the instrument mapping and the parameter settings are independent of one another to some degree. If you want to keep the parameter settings as part of the instrument you’ll need to open the Options menu and select Save Settings to Instrument. Now, whenever the instrument is loaded, the corresponding parameter settings will also be loaded. Looking at the concept in a different way, you can always use the plug-in’s Settings option to save one instrument’s setting and then open those settings in another instance of EXS24.

The approach taken by the EXS24 is certainly unique among software samplers and might not be immediately apparent – or intuitive – if you’re used to working with other samplers such as Kontakt. However, despite its quirks, the EXS24 really delivers thanks to its complete integration into the Logic concept. This is reflected by its ability to accept audio files dropped directly into it from the arrangement to the ease with which it enables you to work with different parameter settings.



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